Navigation Links
Ion gradient


An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. Ionophores are important for ion gradients. The chemiosmotic potential is used as energy storage, chemiosmotic coupling is one of several ways a thermodynamically unfavorable reaction can be driven by a thermodynamically favorable one, I.E by letting the ions diffuse through the high concentration side to the low concentration side through transmembrane proteins which can use them as energy. Several different types of ion gradients exists in biological systems, the most common one is the proton gradient. Transmembrane ATPases or transmembrane proteins with ATPase domains are often used for making and utilizing ion gradients. The enzyme Na+/K+ ATPase use ATP to make a sodium ion gradient and a potassium ion gradient.

Proton gradients

The proton gradient can be used as an intermediate energy storage for heat production and flagellar rotation . Additionally it is an interconvertible form of energy in active transport, electron potential generation, NADPH synthesis and ATP synthesis/hydrolysis.

Some archaea, most notably halobacteria, make proton gradients by pumping in protons from the environment with the help of the solar driven enzyme bacteriorhodopsin, here it is used for driving the molecular motor enzyme ATP synthase to make the necessary conformational changes required to synthesize ATP.

Proton gradients are also be made by bacteria by running ATP synthase in reverse, this is used to drive flagellas.

The F1FO ATP synthase is a reversible enzyme. Large enough quantities of ATP cause it to create a transmembrane proton gradient, this is used by fermenting bacteria which do not have an electron transport chain, and hydrolyze ATP to make a proton gradient, which they use for flagella and transport of nutrients into the cell.

In respiring bacteria under physiological conditions, ATP synthase generally runs in the opposite direction, creating ATP while using the protonmotive force created by the electron transport chain as a source of energy. The overall process of creating energy in this fashion is termed oxidative phosphorylation. Same process takes place in mitochondria, were ATP synthase is located in the inner mitochondrial membrane (so that F1-part sticks into mitochondrial matrix, were ATP synthesis takes place).

See also


'"/>


(Date:6/30/2017)... , June 30, 2017 Today, ... developer and supplier of face and eye tracking ... Featured Product provider program. "Artificial ... innovative way to monitor a driver,s attentiveness levels ... from being able to detect fatigue and prevent ...
(Date:6/14/2017)... (NYSE: IBM ) is introducing several innovative partner startups ... collaboration between startups and global businesses, taking place in ... nine startups will showcase the solutions they have built with ... France is one of the ... percent increase in the number of startups created between 2012 ...
(Date:5/16/2017)... 16, 2017  Veratad Technologies, LLC ( www.veratad.com ), ... and identity verification solutions, announced today they will participate ... May 15 thru May 17, 2017, in ... Trade Center. Identity impacts the lives ... today,s quickly evolving digital world, defining identity is critical ...
Breaking Biology News(10 mins):
Other biology definition